Process of preparing homogeneous alloys of lead



I collecting devices may Patented Au 26, 1930 UNITED STATES PATENT OFFICE PROCESS OF PREPARING HOMOGENEOUS ALLOYS OF LEAD -No Drawing. Appllcattonflled October 24, 1928. Serial The present invention relates to a process of preparing entirely homogeneous alloys of lead with the alkali metals or alkaline earth metals.

\Ve have found that entirely homogeneous alloys of lead with the alkali metals and alkaline earth metals are obtained by compressing in an extrusion press the alloys made in the known manner from lead and an alkali metal and from lead aml an alkaline earth metal respectively. The so pressed alloys, which may originally have been in a powdered or cast form, are advantageously brought into the form of a block before being pressed and are introduced in this state into the extrusion press. The alloys may however also be cast direct-1y into the press. The compressing operation is carried out at temperatures, which may exceed 200 C. .but must not be that at which the respective alloy melts. The pressure to be applied depends on the composition of the alloys and the temperatures employed. If the alloy is caused to pass within the press through a sieve, the alloys may be rendered still more homogeneous.

Vhile the lead alloy is being compressed. it

' may simultaneously be brought into any desired shape. Thus an alloy may be obtained for instance in the form of a tube, it into the nozzle of the press a mandrel is inserted. The alloyed mass and the moulded bodies issuing from the press may be collected in a device serving to reduce their temperature and then allowed to cool slowly. The said be constructed in such a manner, that the alloys are exposed to the air only to a very small extent.

In the process above described, there may be employed besides the alloys of lead with an alkali metal or of lead with an alkaline earth metal, also such'alloys as contain 52 or more admixed metals. By the hitherto used method of casting such alloys, it has scarcely been possible to obtain, for instance, homogeneous alloy of lead with 20% of Na and 0.4% of Ba, whereas such an alloy can be easily obtained by the process of the present application.

The following examples serve to illustrate varied kinds.

20); ot' the alkali metal,

No. 314,843. and in Germany November 5, 1927.

our invention, but they are not intended to limit it thereto:

l. A hot block of a lead-sodium alloy containing 20?? of Na is brought into a suitable form in a press at a tenuierature of 200 C. to 33050 and under a pressure of 90041000 leg/curl. for instance. in the form of a round bar. a small tube. a band or a hollow band, etc. The lead-sodium alloy may also be compressed into acute-angular shapes of the most The \vorkii'ig' conditions are chosen so that the material does not leave. the press too quickly, but has sutlicient time to become coherent. Thus when pressing a tube with a double conic inlet opening and a diameter ot 7.3 mm. (mandrel of 3.3 mm.) at :1 temperature of 310 C. and under a pressure of H00 kg./em. the material leaves the press with a speed 0100 cm. per minute. The small tubes are collected in a device serving to reduce their temperature and which is electrically heated to 200 C, whereupon they lose their plasticity, so that they can easily be cut off by a scissors or saw. The tubes are received in a container which is also heated to 200 C. and in which they slowly cool down to ordinary temperature.

Into a pre-heated press a lead-sodium alloy or lead-potassium alloy, containing is introduced in a fluid state and the mass is compressed while regulating the temperature in such a manner, that the homogeneous lead-alloy when leaving the mouthpiece has a temperature of 260 C. to 330 C. The compressed material being sensitive to air, is :ulvantageously collccted directly in suitable moulds. which are either made air-tight, or are filled with a liquid which does not attack the alloy.

3. A powdered or granulated alloy of lead alkali metal or of lead-alkaline earth metal is first compressed into a briquet and is then pressed out of a hydraulic extrusion press:

he pressures and temperatures of a leadsodium alloy containing 20% of a are indicated in Example 1.

4. A lead alloy containing 201"? of Na and 0.4% of Ba, is cast into a block and com pressed in an extrusion press into a tube. The mould has a double conic inlet opening to 1500 to 1800 kpz/cmd.

of 7.3 mm. diameter by which the material is formed. The mandrel, which is screwed on to a sieve, placed behind the matrix, consists of fine steel, for instance nitrated steel, and has a diameter of 3.3 mm. The temperature of the compressed material is about 310 C. and the required pressure amounts The small tubes leave the opening of the matrix at the rate of about 1 meter per minute.

We claim:

1. The process of making: homogeneous alloys of lead and sodium and shaped bodies therefrom which comprises pressing an alloy of lead and sodium through an extrusion press at temperatures of 260 C. to 330 C. and under a pressure of between 800 to 3000 ken/cm.

2. The process of making homogeneous alloys of lead with an alkali or with an alkaline earth metal and shaped bodies therefrom which comprises pressing an alloy of lead with the said metals through an extension press at a temperature below the melting point of the alloy used and under an initial pressure of at least 600 kgjcmfi.

3. The process of making homogeneous alloys of lead with an alkali or with an alkaline earth metal and shaped bodies therefrom which comprises pressing an alloy of lead with the said metals through an estru sion press at a temperature below the melting pointof the alloy used and under an initial pres ure of at least 600 Kg/cm? into a receptacle while excluding the access of air and causing the pressed alloy to cool in the said receptacle.

4. The process of making homogeneous alloys of lead with an alkali or with an alkaline earth metal and shaped bodies therefrom which comprises pressing an alloy of lead with the said metals through an extru sion press at a temperature below the melting point of the allov used and under an initial pressure of at least 600 ken/cm? into a receptacle heated to about 200 C. while excluding the access of air and causing the pressed alloy to cool in the said receptacle.

5. The process of making l'iomogeneous alloys of lead and sodium and shaped bodies therefrom which comprises pressing an alloy of lead and sodium through an extrusion press at a temperature of between 260 and 330 C. and under a pressure of between 800 and 3000 kg./cm. into a receptacle heated to about 200 C. while excluding the access of air and causing the pressed alloy to cool in the said receptacle.

In testimony whereof, we afiix our signatures.

GEORG KRANZLEIN. RICHARD KARL MULLER.

FRANZ BRUNNTRAGER. HEINRICH JANZ. 

